diff --git a/Michelf/Markdown.php b/Michelf/Markdown.php
index 61778ba..22b1438 100644
--- a/Michelf/Markdown.php
+++ b/Michelf/Markdown.php
@@ -1248,7 +1248,7 @@ class Markdown implements MarkdownInterface {
 	 * Define the emphasis operators with their regex matches
 	 * @var array
 	 */
-	protected $em_relist = array(
+	protected array $em_relist = array(
 		''  => '(?:(?<!\*)\*(?!\*)|(?<!_)_(?!_))(?![\.,:;]?\s)',
 		'*' => '(?<![\s*])\*(?!\*)',
 		'_' => '(?<![\s_])_(?!_)',
@@ -1258,7 +1258,7 @@ class Markdown implements MarkdownInterface {
 	 * Define the strong operators with their regex matches
 	 * @var array
 	 */
-	protected $strong_relist = array(
+	protected array $strong_relist = array(
 		''   => '(?:(?<!\*)\*\*(?!\*)|(?<!_)__(?!_))(?![\.,:;]?\s)',
 		'**' => '(?<![\s*])\*\*(?!\*)',
 		'__' => '(?<![\s_])__(?!_)',
@@ -1268,7 +1268,7 @@ class Markdown implements MarkdownInterface {
 	 * Define the emphasis + strong operators with their regex matches
 	 * @var array
 	 */
-	protected $em_strong_relist = array(
+	protected array $em_strong_relist = array(
 		''    => '(?:(?<!\*)\*\*\*(?!\*)|(?<!_)___(?!_))(?![\.,:;]?\s)',
 		'***' => '(?<![\s*])\*\*\*(?!\*)',
 		'___' => '(?<![\s_])___(?!_)',
diff --git a/Michelf/MarkdownExtra.php b/Michelf/MarkdownExtra.php
index 462adab..2bf1865 100644
--- a/Michelf/MarkdownExtra.php
+++ b/Michelf/MarkdownExtra.php
@@ -1549,17 +1549,17 @@ class MarkdownExtra extends \Michelf\Markdown {
 	 * work in the middle of a word.
 	 * @var array
 	 */
-	protected $em_relist = array(
+	protected array $em_relist = array(
 		''  => '(?:(?<!\*)\*(?!\*)|(?<![a-zA-Z0-9_])_(?!_))(?![\.,:;]?\s)',
 		'*' => '(?<![\s*])\*(?!\*)',
 		'_' => '(?<![\s_])_(?![a-zA-Z0-9_])',
 	);
-	protected $strong_relist = array(
+	protected array $strong_relist = array(
 		''   => '(?:(?<!\*)\*\*(?!\*)|(?<![a-zA-Z0-9_])__(?!_))(?![\.,:;]?\s)',
 		'**' => '(?<![\s*])\*\*(?!\*)',
 		'__' => '(?<![\s_])__(?![a-zA-Z0-9_])',
 	);
-	protected $em_strong_relist = array(
+	protected array $em_strong_relist = array(
 		''    => '(?:(?<!\*)\*\*\*(?!\*)|(?<![a-zA-Z0-9_])___(?!_))(?![\.,:;]?\s)',
 		'***' => '(?<![\s*])\*\*\*(?!\*)',
 		'___' => '(?<![\s_])___(?![a-zA-Z0-9_])',
diff --git a/composer.json b/composer.json
index 9990ce1..73fc79e 100644
--- a/composer.json
+++ b/composer.json
@@ -24,6 +24,7 @@
  		"psr-4": { "Michelf\\": "Michelf/" }
 	},
 	"require-dev": {
-		"phpunit/phpunit": ">= 9.5"
+		"phpunit/phpunit": ">= 9.5",
+		"rector/rector": "^0.11.60"
 	}
 }